JPH0698518B2 - Safety monitoring device for press machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a safety monitoring device for a crank drive type press machine.

<Prior Art> As shown in FIG. 7, in a press machine of this type in which a crank 63 rotating in synchronization with a motor causes a slide 63 to reciprocate via a connecting rod 62, when the manual operation is performed, one slide The operation button is pushed every time the vehicle reciprocates (1 rotation of the crank). The operation button needs to be continuously pressed when the slide 63 descends, but when the slide 63 descends, the slide 63 automatically rises to a predetermined position even if the button is released.

For safety, the slide 63 stop signal (top dead center stop signal) is always generated near the position (top dead center) where the slide 63 moves from up to down, and the slide 63 is decelerated. The dead center stop signal is defined within a limit of θ = 15 ° when the top dead center of the slide 63 is set to 0 at the crank angle θ.
A monitoring signal for that purpose is generated at the limit position. Furthermore, in order to prevent the risk of the slide 63 moving continuously when the operation button is erroneously pressed, a certain position is set during the slide rising process, and the button is pressed again after passing through this position. Without this, the slide 63 does not operate, and when passing through this position, a signal for confirming the passage (restart prevention signal) is generated.

These signals are generated, for example, by providing a rotary cam integrally with the crankshaft 64 and operating a limit switch by the cam profile of the corresponding rotary cam.

<Problems to be solved by the invention> By the way, such a press machine is extremely dangerous to the operator when the above-mentioned top dead center stop signal or restart prevention signal is not generated for some reason, and therefore an emergency stop signal Is output to stop the operation of the press machine.

An example of a conventional safety monitoring device is shown in FIG. 8 and will be briefly described. In the figure, 1 to 9 are flip-flops (hereinafter F.
F circuit), and 10 is an OR circuit. Then, the register for counting the restart prevention signal P ₁ by the F / F circuits 1 and 2 is
Θ = 15 ° by F / F circuits 3 to 5 and F / F circuits 6 to 8
A register that counts each of the monitoring signals P ₃ is configured. Further, the F / F circuit 9 receives the top dead center stop signal P ₂ as a set input.

Next, the operation will be described based on a time chart in FIG.

For example, assume that the signals P ₁ , P ₃ , P ₂ are output at the crank angle position shown in FIG.

When the signals P ₁ , P ₃ and P ₂ are normally output, the signal F ₁ causes the F · F circuit 1 to output “1”. next
Signal P _{3 at} 325 ° causes F / F circuits 3 and 6 to output “1”
However, the signal P ₂ causes the F / F circuit 6 to output "1" and reset the F / F circuit 6. Then, when the signal P _{3 at} 15 ° is input, the F · F circuit 4 counts this and becomes an output “1”, and the F · F circuit 1 is reset and F
・ F circuit 9 is also reset, and F signal is generated by the next signal P _1.
The F circuit 4 is reset. In addition, the FF circuit 6 is a signal
Since the set state at 15 ° signal after being reset by 345 ° signal P _2, but the F · F circuits 7 in the next 325 ° signal as an output "1" due to the subsequent signal P ₂ F · F circuits It is reset by the output from 9.

Therefore, during normal operation, none of the F / F circuits 2, 5 and 8 is set and the output of the OR circuit 10 is not "0".

In such a state, if the signal P ₁ is not output, for example, the F / F circuit 4 is not reset and the counting of the signal P ₃ is continued, and the count output is generated in the F / F circuit 5 (in the set state). As a result, the OR circuit 10 outputs "1" and an abnormal output occurs. Further, when there is no signal P ₂ , the F / F circuit 7 is not reset and the OR circuit 10 produces an abnormal output by the count output from the F / F circuit 8. Furthermore, if the signal P ₃ disappears, F ・
The count output from the F circuit 2 also causes an abnormal output from the OR circuit 10.

As described above, in the conventional safety monitoring device using the F / F circuit, the output of the F / F circuit is not reset at the time of abnormality, so that the operation of the press machine is automatically stopped by using this as an emergency stop signal. Has become.

However, in this device, F / F circuits 2, 5, 8 and OR circuit 1
When 0 becomes a state of output “0” due to a failure, an abnormal output cannot be generated and there is a safety problem instead of fail-safe.

Therefore, instead of the F / F circuit, for example, Japanese Patent Publication No. 45-2
It is conceivable to use a self-holding circuit using an AND gate with a fail-safe logic operation oscillator disclosed in Japanese Patent Publication No. 9054.

An example of the circuit is shown in FIG. 10. The top dead center stop signal P ₂ is directly input to one of the two input terminals of the AND gate 11, and the monitoring signal generated at the limit position via the differentiating circuit 12 to the other. P ₃
Input the differential pulse P ₃ ′ of. The output of the AND gate 11 is input to the differential pulse input side via the diode 13 to form a self-holding circuit, and the output f of the self-holding circuit causes an emergency stop. 14 is a rectifier circuit.

For example, as shown in Fig. 11, the top dead center stop signal of the slide
If the limit switch is turned off when P ₂ is -15 ° to 5 ° and the limit switch is turned on when monitoring signal P ₃ is 15 ° to 20 °, the slide will be at the top dead center. When the position of θ = 15 ° is reached after passing, the output of AND gate 11 becomes “H” level by the positive differential pulse P ₃ ′ input at that time, and then the output of AND gate 11 stops signal P ₂
Self-holding until the fall. Therefore, the waveform of the output f from this self-holding circuit is as shown in FIG.

However, if the output f of the self-holding circuit is used as it is as a signal for emergency stop, it will always be turned off every time the slide makes one reciprocation even during normal operation, as shown in the output waveform above.
A condition occurs. This is irrational because an emergency stop signal is generated for each reciprocation of the slide despite normal operation. This is unavoidable due to the circuit configuration of resetting with the stop signal P ₂ and setting with the generation of the monitoring signal P ₃ .

In view of the above situation, it is an object of the present invention to provide a fail-safe safety monitoring device that uses a fail-safe self-holding circuit and does not generate an emergency stop signal during normal operation.

<Means for Solving the Problems> Therefore, according to the present invention, in the press machine in which the operation button is operated every one slide reciprocation, the motor is activated to reciprocate the slide through the crank, the crank angle of the slide descending section. Stop signal generating means for generating a slide stop signal before 15 °, and to limit the button operation section so that the motor can be restarted only when the operation button is operated again after the predetermined position of the slide rising section Is a signal for detecting the stop signal and the limit signal, and the output is in an excited state in the section from the crank angle of 15 ° to the vicinity of the slide bottom dead center during the sliding operation. And a fail-safe signal that generates a first signal that is in a non-excited state in other sections and a second signal that has an output relationship complementary to the first signal. A fail-safe first self-holding means for inputting the limit signal and the second signal and holding the detection output by the second signal when the limit signal is detected, the stop signal and the second signal. And a second fail-safe second self-holding means for holding the detection output by the second signal when a stop signal is detected, and outputs of the first and second self-holding means
Failsafe third and fourth self-holding means for self-holding up to slide bottom dead center after a crank angle of 15 ° by a signal,
The output of each of the third and fourth self-holding means and the second signal are both provided with fail-safe emergency stop signal generating means for outputting an emergency stop signal when in a non-excited state.

<Operation> According to the above configuration, when both the limit signal for limiting the operation section of the drive button and the slide stop signal are normally generated, the stop signal and the stop signal are generated by the self-holding means by the generation of the first signal and the second signal. The limiting means self-holds up to near the bottom dead center of the slide, and the self-holding output of these excited states causes the output of the emergency stop signal generating means to be in the excited state up to the bottom dead center after the crank angle of 15 ° and outputs the emergency stop signal. Not done. Then, during the other slide movement section, that is, from the vicinity of the slide bottom dead center to the crank angle of 15 °, the second signal generation means
Since the signal is in the excited state, the output of the emergency stop signal generating means is also in the excited state and the emergency stop signal is not output. Therefore, as long as the press machine is in the normal state, the emergency stop is performed in all slide movement sections. No signal is generated.

On the other hand, when the limit signal or the stop means is not generated, the first signal holding means or the second self-holding means does not generate the self-holding output which is the detection output of them, and accordingly, the third signal
Alternatively, the self-holding output is not generated from the fourth self-holding means. Therefore, when the second signal is in the non-excited state, the output of the emergency stop signal generating means is in the non-excited state to generate the emergency stop signal, and the operation of the press machine is stopped.

Moreover, since the signal generating means, the first to fourth self-holding means, and the emergency stop signal generating means have a fail-safe configuration, the output of the emergency stop signal generating means is unexcited when each of these means fails. Then, the operation of the press machine is stopped and the safety is ensured with the same output form as when the emergency stop signal is generated.

<Example> An example of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 21 is a limit signal (hereinafter referred to as a restart prevention signal) for limiting the button operation section so that the motor can be restarted only when the operation button is operated again after the predetermined position of the slide rising section. And 22 are stop signal generating means for generating a stop signal of the slide 63 (hereinafter referred to as a top dead center stop signal) before the crank angle of 15 ° in the slide descending section. For example, a rotary cam having a predetermined cam profile and rotating in synchronization with the crankshaft 64, and a limit switch, and the limit switch is turned on for a predetermined crank angle while the slide 63 is being raised, as shown in FIG. Such a restart prevention signal P ₁ and a top dead center stop signal P ₂ are generated respectively.

Reference numeral 23 is a slide position sensor as a fail-safe signal generating means for emitting complementary first and second outputs P ₃ and ₃ , and its structure is as shown in FIG. 2, for example.

That is, the fan-shaped metal plate 44 shown in FIG. 3 is provided between the transmission coil 42 connected to the oscillator 41 and the reception coil 43 facing the transmission coil 42. Then, the output of the receiving coil 43 is input to the two window comparators 47 and 48 having different window settings via the amplifier 45 and the detection circuit 46, and the rectifier circuits 49 from the window comparators 47 and 48 are input. , and outputs the first and second signals P _{3, 3} of the complementary output relationship through 50. More specifically, the fan-shaped metal plate 44 rotates in synchronization with the rotation of the crankshaft 64, and the crank angle is 15 °.
In section (top dead point stop signal P ₂ must at the latest generation occurrence limit position) to 180 ° (slide bottom dead point),
It passes between the transmitting coil 42 and the receiving coil 43, and therefore the detection output e of the slide 63 during one reciprocation (one rotation of the crank) is as shown in FIG. Further, as shown in FIG. 4, the window setting of each window comparator 47, 48 is set to the level range e ₁ including the steady level of the detection output e in the window comparator 47, and the window comparator 48 in the fan-shaped metal plate. 44 send and receive coils 4
It is set to the level range e ₂ that includes the output level when passing between 2,43.

Therefore, the signals P ₃ and ₃ output from the window comparators 48 and 47 are as shown in FIG. Incidentally, the former upper limit and the latter lower limit are made to overlap with each other to ensure that a self-holding operation described later is obtained.

Reference numeral 24 is a first self-holding circuit using an AND gate made of a fail-safe logic operation oscillator, and the rectification output of the rectification circuit 25 is diode D _{1 in} order to self-hold the restart prevention signal P ₁ by the second signal ₃ of the sensor 23. Have returned through. Reference numeral 26 denotes a second self-holding circuit that holds the top dead center stop signal P ₂ by the second signal ₃ of the sensor 23, and feeds back the output of the rectifier circuit 27 via the diode D ₂ . Further, 28 is the first self-holding circuit
The output of 24 is the first signal P ₃ of the sensor 23 and the crank angle is 15 ° to 18 °.
It is a third self-holding circuit that self-holds in the section up to 0 ° C., and the output is fed back through the rectifier circuit 29 and the diode D ₃ . 30
Is a fourth self-holding circuit that self-holds the output of the second self-holding circuit 26 with the first signal P ₃ , and its output is fed back by the rectifying circuit 31 and the diode D ₄ . 32 is the rectified output of the third self-holding circuit 28 and the second signal ₃ of the sensor 23 and the fourth self-holding circuit
An AND gate as fail-safe emergency stop signal generating means for inputting the rectified output of 30 and each wired or output of the second signal ₃ , 33 is a rectifier circuit.

Next, the operation will be described with reference to the time chart of FIG.

As described above, the rotation of the crank 61, that is, one of the slides 63
The signals P ₁ , P ₂ , ₃ , and P ₃ as shown in the figure are repeatedly output for each round trip.

First, when the restart prevention signal P ₁ is output and inputted to the first self-holding circuit 24 while the slide 63 is moving upward, the second signal ₃ from the sensor 23 causes the signal ₃ to output “0”. The self-holding output (a in the figure) is continued up to °. When the top dead center stop signal P ₂ is normally output before the crank angle of 15 °, the second self-holding circuit 26 also self-holds it by the second signal _{3 and} outputs the self-holding output (in the figure). Similarly, b) continues until the crank angle is 15 °.

Then, the outputs a and b of the first and second self-holding circuits 24 and 26, respectively, are compared with the first signal of the sensor 23 which is complementary to the second signal ₃ .
The third and fourth self-holding circuits 28 and 30 self-hold by the signal P _3, and the respective self-holding outputs (c and d in the figure) are continued until the output of the first signal P ₃ becomes "0". .

Therefore, when the slide 63 descends, the top dead center stop signal P ₂
The output from the third and fourth self-holding circuits 28 and 30 is the section from the crank angle of 15 °, which is the limit position at which the engine must be generated, to the bottom dead center of the slide (crank angle of 180 °)
c, is d "1", indicating that this by its rectified output f the AND gate 32 is excited becomes "1", the signals _{P 1, P 2, 3,} P 3 is normal. Further, in the other slide movement sections, the output of the second signal ₃ of the sensor 23 causes AND
The rectified output f of the gate 32 becomes "1". Therefore, it is possible to solve the problem that the emergency stop signal is output despite the normal operation as in the conventional case.

On the other hand, if the restart prevention signal P ₁ is not output, there is a danger of falling twice, but at this time, the output a of the first self-holding circuit 24
And there is no output c of the third self-holding circuit 28,
AND gate 3 when the second signal ₃ of the sensor 23 becomes "0"
The output f of 2 becomes "0", an emergency stop signal is output, the operation of the press machine is immediately stopped, and the slide 63 can be prevented from falling twice.

Further, even when the top dead center stop signal P ₂ is not output and the slide 63 is not decelerated, the outputs b and d of the second self-holding circuit 26 and the fourth self-holding circuit 30 disappear and the restart prevention signal is output. P
_The emergency stop signal is output as in the case of 1. And
Since the first to fourth self-holding circuits 24, 26, 28, 30 and the slide position sensor 23 and the AND gate 32 of this embodiment have a fail-safe property, when these fail, the output of the AND gate 32 is output. Becomes a non-excited state, and the output form is the same as that of the generation of the emergency stop signal, so the operation of the press machine is stopped and it is safe. Here, in the movement section from the vicinity of the bottom dead center of the slide 63 to the crank angle of 15 °, the second position of the sensor 23
The rectified output f of the AND gate 32 does not become "0" due to the signal ₃ and the emergency stop signal is not output, but there is no problem because this section is the ascending stroke of the slide 63 and is on the safe side.

In this embodiment, one sensor 23 is configured to obtain complementary output-related signals P ₃ and ₃ , but the present invention is not limited to this. For example, apart from the sensor 23, the bottom dead center 180
A sensor using a fan-shaped metal plate 44 'as shown in FIG. 6 that traverses between the transmitting and receiving coils in the section from 15 ° to 15 ° is provided, and two complementary signals P ₃ ,
₃ may be obtained. In addition to this, instead of the sending / receiving coil, a light emitting element and a light receiving element may be opposed to each other and light from the light emitting element may be blocked by a fan-shaped metal plate.

In addition, in the present embodiment, the window settings of the window comparators 47 and 48 are made to partially overlap, but it is not always necessary to overlap them, and the rectified output of the first and second self-holding circuits 24 and 26 is not necessarily required.
A delay time may be given to a and b.

<Effect of the Invention> As described above, according to the present invention, in the slide descending section on the dangerous side, the stop signal and the limit signal are output by the self-holding output of the self-holding means, and the slide on the safe side where the self-holding output disappears. Since the rising section is corrected by the output of one of the signal generating means, the emergency stop signal is output immediately during the normal operation and the emergency stop signal is output immediately during the slide descending section in the abnormal state where the stop and limit signals are not generated. It is possible to eliminate the problems that occur. Furthermore, since it has a fail-safe circuit configuration, an emergency stop signal is always output when there is a failure, which is excellent in safety.

[Brief description of drawings]

FIG. 1 shows a safety monitoring device 1 for a press machine according to the present invention.
FIG. 2 is a circuit diagram showing an embodiment, FIG. 2 is a configuration diagram of a slide position sensor of the above embodiment, FIG. 3 is a drawing of a fan-shaped metal plate of the same sensor, and FIG. 4 is a window setting range of each window comparator of the same sensor. FIG. 5, FIG. 5 is an output waveform time chart for explaining the operation of the above embodiment, FIG. 6 is a drawing of a fan-shaped metal plate of another embodiment of the slide position sensor, and FIG. 7 applies the present invention. FIG. 8 is a schematic configuration diagram of a press machine, FIG. 8 is a conventional circuit diagram using a flip-flop circuit, FIG. 9 is an output waveform time chart in the conventional example as above, and FIG. 10 is a conventional circuit diagram using a self-holding circuit. , FIG. 11 is a time chart of the output waveform. 21 …… Limit signal generating means, 22 …… Stop signal generating means, 23
...... Slide position sensor (signal generation means), 24 …… First
Self-holding circuit, 26 ... Second self-holding circuit, 28 ... Third self-holding circuit, 30 ... Fourth self-holding circuit, 32 ... AND gate (emergency stop signal generating means)

Claims (1)

[Claims] 1. A press machine in which a driving button is operated every one slide reciprocation to start a motor to reciprocate the slide through a crank, and a slide stop signal is generated before a crank angle of 15 ° in a slide descending section. A stop signal generating means and a limit signal for generating a signal for limiting the button operation section so that the motor can be restarted only when the operation button is operated again after the predetermined position in the slide rising section. Generating means and a signal for detecting the stop signal and the limit signal, the output is in the excited state in the section from the crank angle of 15 ° to the vicinity of the slide bottom dead center during the sliding operation, and is in the non-excited state in other sections. 1 signal and fail-safe signal generating means for respectively generating a second signal having an output relationship complementary to the first signal, and the limiting signal A fail-safe first self-holding means for inputting a second signal and self-holding a detection output by the second signal when the limit signal is detected, and the stop signal and the second signal are input, and the second signal is used by the second signal when the stop signal is detected. Fail-safe second self-holding means for self-holding the detection output, and fail-safe second self-holding means for self-holding the outputs of the first and second self-holding means to the slide bottom dead center after the crank angle of 15 ° by the first signal. And third and fourth self-holding means, and fail-safe emergency stop signal generating means for outputting an emergency stop signal when the outputs of the third and fourth self-holding means and the second signal are both in a non-excited state. A safety monitoring device for press machines.